In a general fabrication process of a semiconductor device, annealing techniques are frequently used for activation of impurity atoms, healing of crystal damages and so on. In a conventional furnace annealing, semiconductor substrates are placed in a high temperature ambient created in an electric furnace for a relatively long time period, and the high temperature ambient is liable to influence impurity profiles which are formed in the semiconductor substrates. This sometimes results in undesirable deviation from the designed characteristics, and, for this reason, a lot of rapid annealing techniques are proposed for minimization of the influence due to the heat-treatment.
One of the rapid annealing techniques is well known in the art as a lamp annealing in which a semiconductor substrate is placed in an inert ambient of the atmospheric pressure created in an annealing chamber and treated with a heat radiated from lamps provided in the chamber. The time period is reduced to be about 1/180 with respect to the conventional furnace annealing.
However, a problem is encountered in high-temperature ambient. Namely, the semiconductor substrate is heated about 1000 degrees in centigrade in the annealing chamber, and, for this reason, refractory metal layers or the silicide layers thereof formed on the semiconductor substrate are subjected to mechanical stresses due to shrinkages in volume. The high-temperature ambient further results in insufficient suppression of the driftage of the impurity atom profiles even if the time period is reduced in comparison with the furnace annealing. These problems deteriorates the production yield and the reliability of the semiconductor device, so that a low-temperature annealing method has been sought for improvement of semiconductor manufacturing.